Wood-treating composition



XR 2qr1829081 Patented Eco. 5, 1

UNITED STATE sacs: A

WOOD-TREATING COMPOSITION Ira Hatfield, Webster Groves, Mm. asignor to Monsanto Chemical Company. St. Louis. Mo" a corporation of Delaware No Drawing. Application May 1Q. R89,

Serial No.

realm been found to be especially useful toxic substances for the treatment of wood and wood products to preserve them from attack by molds and micro-organisms such as are responsible for staining and decay. For finished mill work, tetrachlorophenols and pentachlorophenol have been applied to the wood in the form of a liquid composition by dipping. One of the principal requirements of the solvent or carrier which was to be used in such coating or impregnating compositions was that it be readily volatile. Solvents which were used included pine oil. kerosene. Stoddard solvent naphtha. alcohols. etc. It was also essential that the liquid composition should penetrate and spread in the wood when dipped therein. For this purpose various liquids called penetrants have been added to facilitate penetration of the end grain of the wood. and other materials called spreaders. have been added to aid spreading in the wood at right angles to the grain.

However. considerable diillculty has been encountered in using liquid tetrachlorophenol and pentachlorophenol compositions containing volitile solvents such as solvent naphtha. pine oil. alcohols. etc.. for wood coating and impregnation. since, as the solvents volatilize. the poiychlorophenols creep or work to the surface of the wood and so-called "blooming" or crystallization occurs. The crystalline deposit wh ch thus forms as a bloom on the surface. besides having an objectionable appearance on the wood. is easily disengaged by rubbing. brushing or even blowing. when blooming occurs. as it invariably does with such compositions containing volatile solvents, the lull value of the treatment is thus not ali'orded. Besides representing a loss of toxic material when the crystals come to the surface the wood. disengaged crystals from the wood surfacemay present a health hazard.

The principal object of the present invention is to provide a liquid wood-preserving composition containing polychlorophenols which will not bloom on wood or similar materhls coated or impregnated therewith, and will thus reduce the health hazard and increase the ellloacy of a treatment with polychlorophenols. It is a further object o! the invention to provide an improved liquid eomposition ior this purpose an. a method for its application which will produce deeper penetration of the wood and thus provide better protection against stain. decay and similar attacks by micro-organisms.

In my co-pendlng application. Serial No. 181.989. died on December 27. 1937. or which this application is a continuation-in-part. I have disclosed that the above obiects'are admirably realized by using a liquid composition comprising rosin or a similar resinous substance. toxic agents such as polychiorophenols. for example. tetrachlorophenols or pcntachiorophenol. and a solvent such as a high-boiling. relatively nonvolatile oil such as petroleum fuel oil or similar material. An example oi such a liquid woodpreserving composition is one consisting of '5 parts of rosin and 5 parts of pentachlorophenol dissolved in 90 parts of Shell Petroleum Corporation's No. 2 Mid-Continent fuel d}, Such compositions are applied to the wood Ether by dipping, spraying or brushing. and the solvent instead of evaporating rapidly. partially remains on the surface of the wood for a short period and gradually penetrates into the wood. The composition acts both as a penetrsnt and spreader in the body oi the wood.

Heretoiore in using liquid wood-preserving compositions containing volatile solvents. brushin: or spraying were poor methods of applying the compositionsv because suillcient penetration could not be achieved. It was thus necessary to use dipping treatments in which the wood on subjected to contact with liquid compositions ior periods differing according to the degree oi penetration desired. which period might vary from several minutes to a matter of hours. These dipping treatments were in reality soaking treatmerits. By using the coating compositions diaclosed in my copending application and in the present application the coating composition may be spread on the wood by brushing, spraying or dipping. Oi course. dipping treatments are still a preferred method. The composition slowly penetrates into the coated wood as the surface becomes dry. The full penetration and distribution of the treating solution continues over a period of from several hours to a day or more, even alter the oily him has disappeared item the wood surface. The penetration of the wood by the liquid composition even in a brush or spray in: treatment is deeper than that obtained by I soaking in heretotcro used volatile liq mpoaitions i'or period! usually permitted in h dipping treatments. Greater quantities of wood can ihereiore be treated by dipping in any particular dipping vat in a given period according to the invention. since the eiiectiveness oi the treatment is not d-., -..-ndent solely upon the period the wood remains submerged in the treating solution. The solution continues to penetrate into the wood after the wood is removed from the liquid. Since the solvents used in the improved compositions possess high flash points the tire hazard is considerably reduced. The composition is also suitable tor application to wood by pressure treatments according to the methods known in the art.

The rosin or similar resinous substance in the composition has several iunctions. Liquid compositions without rosin when made with highboillng oils. for example. Bhell No. 2 fuel oil or Standard Oil Company of Indians Engine Distillate (Fuel Oil No. 1) still produce blooming on the surface of the wood, although a slight reduction in tendency is noted with various oils of this character. However. I have discovered. as disclosed in my co-peuding application, that rosin and similar resinous substances added in suitable proportions completely suppress blooming. Furthermore. the rosin has an additional function in solubilizing the toxic phenol, for example. pentachlorophenol and tetrachlorophenols. Compositions thus prepared have a shorter drying time on the wood. that is. the surface of wood treated therewith is drier in a shorter period of time than that treated with a similar composition not contining resin. and the period required for penetration of the composition throughout the wood is not lengthened. Wood treated with the composition of my invention shows Just as deep penetration as that treated by means oi compositions not containing a resin. and since my invention also contemplates the use of particular solvents which have both a spreading and a penetrating action. wood thus treated exhibits deeper penetration than that resulting from treatment with compositions prepared with volatile solvents or compositions containing volatile solvents together with socalled spreaders and penetrants.

will. the compositions of the present invention. the paintability and puttiability oi the wood is not substant ally impaired after treatment. Since the compositions dry rapidly when applied to a wood surface. the wood is ready for the application of putty and for painting shortly alter treatment, and since the suriaces are dry and tree from bloom rather than oily and coated with crystals. putty and paint adhere tirmly thereto.

In producing the liquid coating and impregnating compositions I dissolve approximately 6% by weight oi a tetrachlorophenol or technical mixtures oi tetraehlorophenols. or pentachlorophenol in by weight of a iuel oil or a similar petroleum hydrocarbon oil, preferably one having a high ilash point. Smaller proportions of the polyehlorophenol component may be used but the resulting lmprexnated wood is not as completely protected. Greater proportions of the toxic materials in the liquid compositions may be used but these greater additions are. of course. limited to some extent by the solvent power of the petroleum oil and by economic considerations. The compositions must be stable and must completely retain all the polychlorophenol without any separation or crystallization at outdoor temperatures. E'or proionsed fungicidal protection a wood impregnated with a composition containing 5% or polychlorophenoi according to the'method oi the invention is eminently satisfactory.

The petroleum oils which i prefer for the pur- I poses of the invention are those having char acteristics within the approximate ranses given hereinbelow:

Gravity A. P. I. at 80 F 20-40 Flash point A. 8. T. M. (Tagliabue Closed Cup) 140' 1'. and higher Viscosity Baybolt Universal at 1' 30-40 A. E. 'l. M. distillation range 300-450- i". w

Petroleum solvents boiling at lower ranges than those hereinabove specified may be used provided they dissolve the desired proportion oi the toxic chemical. The odor and color of the all must also be considered (or the particular application. For some purposes. odorous oils or oils oi dark color are not objectionable but ior certain uses where color must no. be imparted to the wood. light-colored relatively odorless oils are essential. Oils oi high boiling range are desirable, as hereinbeiore stated.

Although petroleum oil solvents are specifically contemplated. high-boiling chlorinated solvents and aliphatic as well as aromatic solvents may be used. The resin or similar resinous material has proven eilective in preventing the "blooming" tendency which the solvents might engender. Of course, economic considerations are in iavor oi the use of petroleum solvents or their mixtures with small proportions of other solvents. 5

In using the compositions of the invention, diiierent solvent mixtures may be used in the treatment of wood products oi diflerent thicknesses. Thus. for example. a mixture oi lowboiling and high-boiling petroleum solvents ls eminently suitable for the preparation of compositions for treatment of thin wood boards. For thicker boards. greater proportions oi hishboiling solvents are desirable to facilitate deeper penetration.

In my copendlng application referred to hereinabove 1 have specifically disclosed as resinous constituents of my improved wood-treatins compositions. rosin. cumarone-indene resins. petroleum resins such as those sold under the trade name Banto-Resin", rosin residues. aster gum. rosin esters. petroleum tar resins and resins derived irom rosin such as that designated by the trade name "Vlnsol".

oi the various resins found useful. eater sum and rosin esters similar thereto are considerably more eiiective in preventing blooming. and woodtreating compositions prepared ihereirom possess a number of other unexpected advantages.

Ester gum is the product resulting from the esteriflcation oi rosin with glycerol and consists essentially therefore oi glycerol abietate. Esters oi rosin or abietic acid with other alcohols. monohydric as well as polyhydric. may be substituted therefor without substantial loss of the advantages resulting from the use of ester gum in my wood-treating compositions. The rosin esters are preferably neutral. that is. substantially completely esteriiled pro ucts. Rosin salts such as limed rosin are not the equivalent of rosin esters. 70 Lirned rosin iorms some calcium pentacnlorophenate in pentachlorophenol solutions and the calcium pentochlorophenate is more subject to leaching by water than pentachlomphenol.

in comparison with polychlorophenol woodll e: compositions prepared with roein. those mnaredwithroainesterssucnasestergmn have lower solution temperatures, have a color ch is more stable in the presence of metals and somewhat smaller proportions of rosin ester mm used to prevent blooming on wood, that is. ester gum. ior example, is a somewhat more eiimtive bloom-controlling constituent than rosin.

Solution temperature is the lowerst temmrature at which a definite quantity of the p01!- chlorophenol will dissolve completely in a definite quantity of solvent containing the resin which was previously dissolved therein. ature is determined by slowly heating the solvent m8 tempercontalning the resin in which is suspended the polycluorop'ienol. The solubilising sheet of the resin is thereby compared with that of other resins by means oi this determination.

Th erences between compositions con taining sin from those containing rosin esters is illustrated in the ioilowing results:

Solution temperature-Five grams of pure pentachiorophenol were added to grams oi Shell Ho. 2 incl oil. 'Ihe mixture was heated slowly and stirred. The pentschlorophenoi was dissolved completely when the temperature reached-44.5 C. By adding 5 grams of Grade-K rosin to DO grams of the same moi oil and after solution of the rosin therein, adding 5 parts of pure pentachlorophenol and heatin slowly as before, it was i'ound that the solution temperature was 42.0 0.. that is. the solution temperature was reduced to 2.5 C. as a result of the presence oi the rosin. By using 5 grams oi Synthe-Copal ester gum (Reichhold Chemicals) instead of the rosin. the solution temperature was found to be 39.5 C. or a reduction of 5.0 C.

Color stability in presence of watch-Compositions were prepared consisting oi 5 parts by weight of pentachlorophenol, 90 parts by weight of Shell No. 2 incl oil and 6 parts by weight of the resins indicated below. Each-oi these compositions were placed in black iron drums {L C. C. 5 E) and.their colors were observed at various intervals. The colorwas determined by comperison with MP5 color standards. The ioilowing results were obtained:

Hydrogenated wood rosin-(Stabylitel-original 3 which darkened to 8+ in 16 hours Gradc-K-roein-original 4 which darkened to ii in 3 days 'Paraniet Pale Ester Gum No. 2--original 3% which darkened to 8 in 8 months statue-Canal fiter Gum-oriainal 3 which darkened to 8 in 3 months and remained 8 for 3 additional months of desirable surface-drying time will alsooe variable but will generally be approximately equal to or greater than the weight of the toxic substance. in general the toxic polyehlorophenol should be present in proportions oi from it to 5 or more parts by weight to parts by weight oi the composition. Greater than 5 parts by weight 0! polychlorophcnol to 100 parts of the composition may be used it a solvent having sumcient solvent power for the pol!- chlomphenol is employed or ii sinhcient resin is used to increase the solvent power oi the solvent (or the poiyohlorophenoi to the desired aatent. The proportion oi ester gum or similar rosin ester for use in the compositions will vary ircm about i to 19 or more parts per ibO parts by weight of the composition depending Won the proportion of polychlorophenol present the blooming of which is to be prevented. Blight diilerenoes in blooming oi the compositions is noted with diflerent woods and these variations may be considered in providing a composition (or the particular use.

The liquid compositions of the invention are applicable to the treatment of wood and wood products which are particularly subject to decay and stain. especially those materials which are subjected to humid and moist conditions which favor the development of stain and decay. me! are also useful (or protecting these materials iron: termite attack. Celiuioeic materials such as cloths. papers. wall boards and the like which are also subject to attack by micro-organisms and insects can be similarly ted with these compositions.

The compositions may be modified by the addition thereto oi secondary materials such as wetting agents. water-mpelients. insect-repellents. fire retardants, pigments or dyes. substances which exert a synergistic action on the chlorinated phenols and other materials having iavorable action on the impregnation or penetration of the composition or have a desirable action in further protecting or enhancing the value o! the treated article.

In this specification and in the claims tetrachlorophenol is to be understood to-signiiy any of the isomers or s mixture oi the isomers. it is also to be understood that the foregoing description is but a preferred embodiment oi the invention and that changes and modifications may be made therein without departing substantially from the invention which is defined in the appended claims.

Although the foregoing description has bees specifically directed to the use oi tetrachloroplienols and pentachlorophenol as the toxic component of the composition it is evident that the blooming oi compositions wntaining other chlorinated phenolic toxics such as chlorinated cresols, chlorinated coal tar acids. chlorinated wood-tar acids. chlorinated naphthols, and chicrinated hsdroxydiphenyls may likewise be prevented.

What I claim is:

i. A non-blooming liquid coatina and impregnsting composition ior the treatment oi wood and similar ceiluloeic materials to protect them from decay by molds and micro organisms. comprising a. chlorinated phenol dissolved in a solvent therefor in sufllcient concentration t5 provide. when applied to wood and cellulosic materials. substantial protection from attack and decoy by molds and micro-organisms and having a rosin ester dissolved in said solvent in sumcient concentration to prevent blooming on wood and similar oeiluloslc materials treated with the quid composition.

1. Aconipositionasdeilnedlnoiaim iandtuh ther characterised in that the rosin ester is an ester gum.

' 5. A composition as defined in claim 1 and mither characterized in that the solvent is a petroleum solvent.

" Ianisma. comprising a chlorinated phenol selected from the group coneistinl oi tetrachlorophenols and pentachlorophenol dissolved in a petroleum hydrocarbon oil having a boiling range within the range oi approximately 300 to 750' I". in auflicient concentration to provide, yhen applied to wood and similar celluioslc materials. substantial protection iromattack and decay by molds and micro-organisms. and having esteraum dissolved in said petroleum hydrocarbon all in cuflicient concentration to prevent bloomin; on wood and similar ceiluloaio material; treated with the liquid compoaitim.

7. A nonblooming liquid coating and immnoting composition for the treatment of wood and aimilar cellulosic materials to protect them from attack by molds and micro-oreaniaml. comprising the folowing materiala in aporozimately the iollowing proportions: 5 part: by weight of pentachlorophenol, 5 part: by Ieiaht oi ester gum. and 90 parts by weight of a petroleum iwdrocarbon i'uel oil having a boiling range within the range of approximately 300 to 760' I.

8. A non-blooming liquid coating and impreghating composition {or the treatment oi wood and similar celluloaic materials to protect them iroin attack by molds and micro-organism; and insects. comprising the following materials in approximately the following proportions: 5 part by weight oi tetra-ehlorophenoi. 5 part: by weight of eater gum. and 90 part: by weight of a petroleum hydrocarbon fuel oil having a boiling ranae within the range oi approzimately 300' to 750 l".

IRA HATFIELD. 

